How to Use a 45-Degree Locking Router Bit


The 45-Degree Locking Router Bit is used to produce extra strong miter joints in boxes, beams, columns, cabinet face frame corners, and to glue up matching board stock. This bit, when set up properly, can mill both pieces without having to move the bit. One piece is run vertically on the router table and the other is run horizontally. This bit is to be used in a router table only.

Step 1

Put on the safety glasses and the hearing protection.

Step 2

Install the 45-degree lock miter bit into the router.

Step 3

Use the table saw to cut several 3-inch-wide by 12-inch-long scraps of material in the same thickness as your projects stock. These will be used to dial in the router bit and fence for a perfect fit.

Step 4

Take a piece of scrap material and place it against the router table fence. Adjust the 45-degree miter bit height so that the top of the bit and the top of the material are the same height.

Step 5

Adjust the router tables fence so that the outside edge of the fence is is in line with the inside top edge of the 45-degree miter bit.

Step 6

Run a piece of scrap through the router in the horizontal and one in the vertical position.

Step 7

Place both pieces of scrap test material on a flat surface and fit together in the horizontal position. Check to see if the scrap test pieces are flush with each other.

Step 8

Repeat Steps 6 and 7, adjusting the fence or bit height each time, until they are flush.

Step 9

When they are locked together in a horizontal position and are flush with each other, the 45-degree locked miter joint bit is set up correctly.

Tips and Warnings

  • Only use the bit with a router table. Adjust the router speed to a maximum of 1800 RPM.

Things You'll Need

  • Safety glasses
  • Hearing protection
  • Table saw
  • Scrap material
  • Router
  • 45-degree router bit


  • Instructions
  • "Complete Illustrated Guide to Routers"; Lonnie Bird; 2006
Keywords: locked miter joint, vertical position, horziontal position

About this Author

Jim Wildman served in the United States Marine Corps as a Communication Chief for 10 years. After his tour of duty in Desert Storm he attended Oklahoma State University receiving his Bachelor of Architecture. He worked as an architect for 10 years before starting his own design/build company. He began writing in 2009 for Demand Studios and published on eHow.

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